Risk factors for seizure recurrence in children after first unprovoked seizure

Abstract

Background: The question of whether to treat a patient after a first unprovoked seizure is controversial. This prospective study assessed the time to recurrence and risk factors for seizure recurrence after a first unprovoked seizure in children.

Methods: Participants were recruited between 1 July 1997, and 30 June 2009. Eligible candidates were children between 1 month and 15 years old who presented with their first unprovoked afebrile seizure. After enrollment, recurrence of seizures was investigated. All participants were followed for at least 2 years. Log-rank test was used for bivariate analysis to check associations, and hazard ratios were used to analyze variables and clinical outcome (recurrence) during follow-up.

Results: Of 73 subjects, 42 (57.5%) experienced recurrence. The overall product-limit estimate of recurrence was 61.9% at 6 months, 85.7% at 1 year, and 95.2% at 2 years after seizure onset, respectively. Incidence of recurrence with partial and generalized seizures was 69.0% and 31.0%, respectively. Children with partial seizures had recurrence significantly more often than those with generalized seizures (P < 0.001). Recurrent seizures occurred after normal findings on electroencephalogram (EEG) in 21.4%, after generalized spike-and-wave complexes in 16.7%, and after focal epileptic discharge in 61.9%. Children with focal epileptic discharge had recurrence significantly more often than children with normal EEG findings (P < 0.001).

Conclusion: The time to seizure recurrence after first unprovoked seizure may be within 1 year, and particularly within 6 months; and partial seizure and abnormal EEG with focal epileptic discharge may be risk factors for seizure recurrence.

Keywords: first unprovoked seizure; focal discharge; partial seizure; seizure recurrence; time to recurrence.